Cannot apply .df file while Replication server is running - error 2623

Cannot apply .df file while the Replication Server is running.
Replication source database in use by another user when attempting to load delta.df to update schema
Replication Server holds a schema lock on a source database.
Unable to apply an online schema change when Replication server is active.
The Replication Agent on the target database is not running.

Even when no users are connected to the source or target database the schema update stalls with error 2623

This behavior is by design

• When the Replication Agent or target database are not running, the schema is locked by the Replication Server for recovery purposes.
• When the RPLS and RPLA then establish contact, Schema updates are not allowed until the Replication server has completed performing synchronization. If schema updates are being performed when failure recovery synchronization begins, source database updates will block until failure recovery is complete.

To apply schema updates to the source replication enabled database:

1.  If the Replication Server is waiting to connect to the Agent or the Replication Server is running but the Target database or Replication Agent are not online:

• Wait until the connect-timeout server property expires
• If defer-agent-startup mode is in effect, then run "DSRUTIL -C canceldefer" once the connect-timeout has expired.

Online Schema changes can be applied to the source database once the Replication Server terminates (read: the replication server will no longer lock the schema).
Ensure sufficient AI extents to record the associated schema update transaction notes.

2.  If the Target database and Replication Agent is online and synchronisation is being performed:

Wait until the databases have synchronised before applying schema updates online. The schema update will then be propogated to the target database.

3. Otherwise, schema updates can be applied offline against the source database, ensuring sufficient AI extents to record the associated transaction notes.

Progress Articles:  

 Can't update schema while OpenEdge Replication is active